[gtk+] cssimage: Add GtkCssImageCrossFade

[Benjamin Otte <otte src gnome org>]

commit d853a8f2f72e1261b0d301be6ba8a480a37a3e45
Author: Benjamin Otte <otte redhat com>
Date:   Mon Apr 2 03:25:30 2012 +0200

    cssimage: Add GtkCssImageCrossFade
    
    Supports the cross-fade() css notation the way the old CSS3 specs did.
    
    The main reason for adding it is supporting image transitions though.

 gtk/Makefile.am                   |    2 +
 gtk/gtkcssimage.c                 |    4 +-
 gtk/gtkcssimagecrossfade.c        |  269 +++++++++++++++++++++++++++++++++++++
 gtk/gtkcssimagecrossfadeprivate.h |   59 ++++++++
 4 files changed, 333 insertions(+), 1 deletions(-)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index 54faaa1..5559b07 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -428,6 +428,7 @@ gtk_private_h_sources =		\
 	gtkcsscustompropertyprivate.h \
 	gtkcsseasevalueprivate.h	\
 	gtkcssenumvalueprivate.h	\
+	gtkcssimagecrossfadeprivate.h	\
 	gtkcssimagegradientprivate.h	\
 	gtkcssimagelinearprivate.h	\
 	gtkcssimageprivate.h	\
@@ -635,6 +636,7 @@ gtk_base_c_sources = 		\
 	gtkcsseasevalue.c	\
 	gtkcssenumvalue.c	\
 	gtkcssimage.c		\
+	gtkcssimagecrossfade.c	\
 	gtkcssimagegradient.c	\
 	gtkcssimagelinear.c	\
 	gtkcssimageurl.c	\
diff --git a/gtk/gtkcssimage.c b/gtk/gtkcssimage.c
index a89402e..66ceffe 100644
--- a/gtk/gtkcssimage.c
+++ b/gtk/gtkcssimage.c
@@ -22,6 +22,7 @@
 #include "gtkcssimageprivate.h"
 
 /* for the types only */
+#include "gtk/gtkcssimagecrossfadeprivate.h"
 #include "gtk/gtkcssimagegradientprivate.h"
 #include "gtk/gtkcssimagelinearprivate.h"
 #include "gtk/gtkcssimageurlprivate.h"
@@ -324,7 +325,8 @@ gtk_css_image_get_parser_type (GtkCssParser *parser)
     { "-gtk-gradient", _gtk_css_image_gradient_get_type },
     { "-gtk-win32-theme-part", _gtk_css_image_win32_get_type },
     { "linear-gradient", _gtk_css_image_linear_get_type },
-    { "repeating-linear-gradient", _gtk_css_image_linear_get_type }
+    { "repeating-linear-gradient", _gtk_css_image_linear_get_type },
+    { "cross-fade", _gtk_css_image_cross_fade_get_type }
   };
   guint i;
 
diff --git a/gtk/gtkcssimagecrossfade.c b/gtk/gtkcssimagecrossfade.c
new file mode 100644
index 0000000..43d0b6d
--- /dev/null
+++ b/gtk/gtkcssimagecrossfade.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright  2012 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte gnome org>
+ */
+
+#include "config.h"
+
+#include <string.h>
+
+#include "gtkcssimagecrossfadeprivate.h"
+
+#include "gtkcssnumbervalueprivate.h"
+
+G_DEFINE_TYPE (GtkCssImageCrossFade, _gtk_css_image_cross_fade, GTK_TYPE_CSS_IMAGE)
+
+static int
+gtk_css_image_cross_fade_get_width (GtkCssImage *image)
+{
+  GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
+  int start_width, end_width;
+
+  if (cross_fade->start)
+    {
+      start_width = _gtk_css_image_get_width (cross_fade->start);
+      /* no intrinsic width, what now? */
+      if (start_width == 0)
+        return 0;
+    }
+  else
+    start_width = 0;
+
+  if (cross_fade->end)
+    {
+      end_width = _gtk_css_image_get_width (cross_fade->end);
+      /* no intrinsic width, what now? */
+      if (end_width == 0)
+        return 0;
+    }
+  else
+    end_width = 0;
+
+  return start_width + (end_width - start_width) * cross_fade->progress;
+}
+
+static int
+gtk_css_image_cross_fade_get_height (GtkCssImage *image)
+{
+  GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
+  int start_height, end_height;
+
+  if (cross_fade->start)
+    {
+      start_height = _gtk_css_image_get_height (cross_fade->start);
+      /* no intrinsic height, what now? */
+      if (start_height == 0)
+        return 0;
+    }
+  else
+    start_height = 0;
+
+  if (cross_fade->end)
+    {
+      end_height = _gtk_css_image_get_height (cross_fade->end);
+      /* no intrinsic height, what now? */
+      if (end_height == 0)
+        return 0;
+    }
+  else
+    end_height = 0;
+
+  return start_height + (end_height - start_height) * cross_fade->progress;
+}
+
+static void
+gtk_css_image_cross_fade_draw (GtkCssImage        *image,
+                               cairo_t            *cr,
+                               double              width,
+                               double              height)
+{
+  GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
+
+  if (cross_fade->progress <= 0.0)
+    {
+      if (cross_fade->start)
+        _gtk_css_image_draw (cross_fade->start, cr, width, height);
+    }
+  else if (cross_fade->progress >= 1.0)
+    {
+      if (cross_fade->end)
+        _gtk_css_image_draw (cross_fade->end, cr, width, height);
+    }
+  else
+    {
+      cairo_surface_t *surface;
+
+      if (cross_fade->start && cross_fade->end)
+        {
+          /* to reduce the group size */
+          cairo_rectangle (cr, 0, 0, width, height);
+          cairo_clip (cr);
+
+          cairo_push_group (cr);
+
+          _gtk_css_image_draw (cross_fade->start, cr, width, height);
+
+          surface = _gtk_css_image_get_surface (cross_fade->end,
+                                                cairo_get_target (cr),
+                                                width, height);
+          cairo_set_source_surface (cr, surface, 0, 0);
+          cairo_paint_with_alpha (cr, cross_fade->progress);
+          cairo_surface_destroy (surface);
+
+          cairo_pop_group_to_source (cr);
+          cairo_paint (cr);
+        }
+      else if (cross_fade->start || cross_fade->end)
+        {
+          surface = _gtk_css_image_get_surface (cross_fade->start ? cross_fade->start : cross_fade->end,
+                                                cairo_get_target (cr),
+                                                width, height);
+          cairo_set_source_surface (cr, surface, 0, 0);
+          cairo_paint_with_alpha (cr, cross_fade->start ? 1.0 - cross_fade->progress : cross_fade->progress);
+          cairo_surface_destroy (surface);
+        }
+    }
+}
+
+static gboolean
+gtk_css_image_cross_fade_parse (GtkCssImage  *image,
+                                GtkCssParser *parser,
+                                GFile        *base)
+{
+  GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
+  GtkCssValue *number;
+
+  if (!_gtk_css_parser_try (parser, "cross-fade(", TRUE))
+    {
+      _gtk_css_parser_error (parser, "Expected 'cross-fade('");
+      return FALSE;
+    }
+
+  cross_fade->start = _gtk_css_image_new_parse (parser, base);
+  if (cross_fade->start == NULL)
+    return FALSE;
+
+  if (!_gtk_css_parser_try (parser, ",", TRUE))
+    {
+      _gtk_css_parser_error (parser, "Missing comma after first image");
+      return FALSE;
+    }
+
+  cross_fade->end = _gtk_css_image_new_parse (parser, base);
+  if (cross_fade->end == NULL)
+    return FALSE;
+
+  if (!_gtk_css_parser_try (parser, ",", TRUE))
+    {
+      _gtk_css_parser_error (parser, "Missing comma after second image");
+      return FALSE;
+    }
+
+  if (!_gtk_css_parser_try (parser, ")", TRUE))
+    {
+      _gtk_css_parser_error (parser, "Missing closing bracket");
+      return FALSE;
+    }
+
+  number = _gtk_css_number_value_parse (parser, GTK_CSS_PARSE_PERCENT | GTK_CSS_POSITIVE_ONLY);
+  if (number == NULL)
+    return FALSE;
+  cross_fade->progress = _gtk_css_number_value_get (number, 1);
+  _gtk_css_value_unref (number);
+
+  if (cross_fade->progress > 100)
+    {
+      _gtk_css_parser_error (parser, "Percentages ovre 100%% are not allowed");
+      return FALSE;
+    }
+  cross_fade->progress /= 100.0;
+
+  return TRUE;
+}
+
+static void
+gtk_css_image_cross_fade_print (GtkCssImage *image,
+                                GString     *string)
+{
+  GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
+
+  g_string_append (string, "cross_fade(");
+  if (cross_fade->start)
+    _gtk_css_image_print (cross_fade->start, string);
+  else
+    g_string_append (string, "none");
+  g_string_append (string, ",");
+  if (cross_fade->end)
+    _gtk_css_image_print (cross_fade->end, string);
+  else
+    g_string_append (string, "none");
+  g_string_append (string, ",");
+  g_string_append_printf (string, "%g%%", cross_fade->progress * 100.0);
+  g_string_append (string, ")");
+}
+
+static void
+gtk_css_image_cross_fade_dispose (GObject *object)
+{
+  GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (object);
+
+  g_clear_object (&cross_fade->start);
+  g_clear_object (&cross_fade->end);
+
+  G_OBJECT_CLASS (_gtk_css_image_cross_fade_parent_class)->dispose (object);
+}
+
+static void
+_gtk_css_image_cross_fade_class_init (GtkCssImageCrossFadeClass *klass)
+{
+  GtkCssImageClass *image_class = GTK_CSS_IMAGE_CLASS (klass);
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  image_class->get_width = gtk_css_image_cross_fade_get_width;
+  image_class->get_height = gtk_css_image_cross_fade_get_height;
+  image_class->draw = gtk_css_image_cross_fade_draw;
+  image_class->parse = gtk_css_image_cross_fade_parse;
+  image_class->print = gtk_css_image_cross_fade_print;
+
+  object_class->dispose = gtk_css_image_cross_fade_dispose;
+}
+
+static void
+_gtk_css_image_cross_fade_init (GtkCssImageCrossFade *image_cross_fade)
+{
+}
+
+GtkCssImage *
+_gtk_css_image_cross_fade_new (GtkCssImage *start,
+                               GtkCssImage *end,
+                               double       progress)
+{
+  GtkCssImageCrossFade *cross_fade;
+
+  g_return_val_if_fail (start == NULL || GTK_IS_CSS_IMAGE (start), NULL);
+  g_return_val_if_fail (end == NULL || GTK_IS_CSS_IMAGE (end), NULL);
+
+  cross_fade = g_object_new (GTK_TYPE_CSS_IMAGE_CROSS_FADE, NULL);
+  if (start)
+    cross_fade->start = g_object_ref (start);
+  if (end)
+    cross_fade->end = g_object_ref (end);
+  cross_fade->progress = progress;
+
+  return GTK_CSS_IMAGE (cross_fade);
+}
+
diff --git a/gtk/gtkcssimagecrossfadeprivate.h b/gtk/gtkcssimagecrossfadeprivate.h
new file mode 100644
index 0000000..5492931
--- /dev/null
+++ b/gtk/gtkcssimagecrossfadeprivate.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright  2012 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte gnome org>
+ */
+
+#ifndef __GTK_CSS_IMAGE_CROSS_FADE_PRIVATE_H__
+#define __GTK_CSS_IMAGE_CROSS_FADE_PRIVATE_H__
+
+#include "gtk/gtkcssimageprivate.h"
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_CSS_IMAGE_CROSS_FADE           (_gtk_css_image_cross_fade_get_type ())
+#define GTK_CSS_IMAGE_CROSS_FADE(obj)           (G_TYPE_CHECK_INSTANCE_CAST (obj, GTK_TYPE_CSS_IMAGE_CROSS_FADE, GtkCssImageCrossFade))
+#define GTK_CSS_IMAGE_CROSS_FADE_CLASS(cls)     (G_TYPE_CHECK_CLASS_CAST (cls, GTK_TYPE_CSS_IMAGE_CROSS_FADE, GtkCssImageCrossFadeClass))
+#define GTK_IS_CSS_IMAGE_CROSS_FADE(obj)        (G_TYPE_CHECK_INSTANCE_TYPE (obj, GTK_TYPE_CSS_IMAGE_CROSS_FADE))
+#define GTK_IS_CSS_IMAGE_CROSS_FADE_CLASS(obj)  (G_TYPE_CHECK_CLASS_TYPE (obj, GTK_TYPE_CSS_IMAGE_CROSS_FADE))
+#define GTK_CSS_IMAGE_CROSS_FADE_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_CSS_IMAGE_CROSS_FADE, GtkCssImageCrossFadeClass))
+
+typedef struct _GtkCssImageCrossFade           GtkCssImageCrossFade;
+typedef struct _GtkCssImageCrossFadeClass      GtkCssImageCrossFadeClass;
+
+struct _GtkCssImageCrossFade
+{
+  GtkCssImage parent;
+
+  GtkCssImage *start;
+  GtkCssImage *end;
+  double progress;
+};
+
+struct _GtkCssImageCrossFadeClass
+{
+  GtkCssImageClass parent_class;
+};
+
+GType          _gtk_css_image_cross_fade_get_type             (void) G_GNUC_CONST;
+
+GtkCssImage *  _gtk_css_image_cross_fade_new                  (GtkCssImage      *start,
+                                                               GtkCssImage      *end,
+                                                               double            progress);
+
+G_END_DECLS
+
+#endif /* __GTK_CSS_IMAGE_CROSS_FADE_PRIVATE_H__ */